from hashlib import md5 from base64 import b64decode from base64 import b64encode from Crypto.Cipher import AES from Crypto.Random import get_random_bytes from random import randrange import string alphabet = string.ascii_lowercase + strin…

#nullconHackIM2019 https://ctftime.org/task/7514 4 bit key space is brute forceable so how about 48 bit key space? flag is hackim19{decrypted flag} 16 bit plaintext: b'0467a52afa8f15cfb8f0ea40365a6692' flag: b'04b34e5af4a1f5260f6043b8b9abb…

#aeroctf2021 #good_challenges_2021 #!/usr/bin/env python3.8 from gmpy import next_prime from random import getrandbits def bytes_to_long(data): return int.from_bytes(data, 'big') class Wardrobe: @staticmethod def create_boggarts(fear, dang…

#LINECTF2022 from present import Present from Crypto.Util.strxor import strxor import os, re class CTRMode(): def __init__(self, key, nonce=None): self.key = key # 20bytes self.cipher = DoubleRoundReducedPresent(key) if None==nonce: nonce …

#zer0ptsCTF2021 from Crypto.Cipher import AES from Crypto.Random import get_random_bytes from binascii import hexlify, unhexlify from hashlib import md5 import os import signal from flag import flag keys = [md5(os.urandom(3)).digest() for …

meet-in-the-middle attackってこうやって出すのかなるほどな〜という問題。 import sys from hashlib import sha256 from Crypto.Cipher import DES SECRET = 0xa########e # remember to erase this later.. seed = b'secret_sauce_#9' def keygen(s): key…

RSA from hashlib import sha256 from flag import flag def encrypt_chunk(N, e, chunk): x = int.from_bytes(chunk, 'big') y = randint(0, 256^len(chunk)) return Zmod(N)(x*y)^e p, q = [random_prime(2^1024) for _ in range(2)] N = p * q e = 0x1000…